Rhododendron dies off

Question from Toni Fernandez

Hi,

I seem to have a problem with my plants, they seems to be OK until the top leaves sort of dry out and curl up and this affects the flower buds too, one died already last year, the other two are producing new green leaves from the top (where the buds were), but not sure they'll not get the problem too!

I think I am doing everything right (mulching, pH, moisture, etc), but plants are simply not happy!! Please help!!

I'll try to add some pics asap

Thanks a lot!